Autoradiographic imaging of altered synaptic αβγ2 and extrasynaptic αβ GABAA receptors in a genetic mouse model of anxiety

Saku T. Sinkkonen, Bernhard Luscher, Hartmut Lüddens, Esa R. Korpi

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

To image the possible alterations in brain regional GABAA receptor subtype properties in a genetic animal model of human anxiety, mice heterozygous for the deletion of GABAA receptor γ2 subunit (γ2+/-) were studied using ligand autoradiographic assays on brain cryostat sections. The [35S]TBPS binding assay was designed to reveal impaired GABA and channel site coupling shown to be more prominent in recombinant α1/6β3 than in α1/2β3γ2 or β2 subunit-containing GABAA receptors expressed in HEK 293 cells. Increased GABA-insensitive [35S]TBPS binding in the γ2 +/- mouse brains was evident in the cerebral cortex and in subcortical regions, the alterations being regionally similar to the loss of γ2 subnunit-dependent benzodiazepine (BZ) sites as revealed by [ 3H]Ro 15-4513 autoradiography. As the γ2 subunit protein is needed for synaptic clustering of GABAA receptors, these results indicate that the extrasynaptic αβ3 receptors can be visualized in vitro as atypical GABA-insensitive [35S]TBPS binding sites. The results suggest that GABAAergic synaptic inhibition is widely decreased in the brains of anxiety-prone γ2+/- mice, while extrasynaptic GABAA receptors are increased. These autoradiographic imaging findings further demonstrate the need to develop GABAA receptor subtype-selective in vivo ligands to aid in assessing the contributions of various subcellular receptor populations in anxious and other patient groups.

Original languageEnglish (US)
Pages (from-to)539-547
Number of pages9
JournalNeurochemistry International
Volume44
Issue number7
DOIs
StatePublished - Jan 1 2004

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Genetic Models
GABA-A Receptors
Anxiety
gamma-Aminobutyric Acid
Brain
Ligands
HEK293 Cells
Protein Subunits
Autoradiography
Benzodiazepines
Cerebral Cortex
Cluster Analysis
Animal Models
Binding Sites
Population
tert-butylbicyclophosphorothionate

All Science Journal Classification (ASJC) codes

  • Cellular and Molecular Neuroscience
  • Cell Biology

Cite this

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title = "Autoradiographic imaging of altered synaptic αβγ2 and extrasynaptic αβ GABAA receptors in a genetic mouse model of anxiety",
abstract = "To image the possible alterations in brain regional GABAA receptor subtype properties in a genetic animal model of human anxiety, mice heterozygous for the deletion of GABAA receptor γ2 subunit (γ2+/-) were studied using ligand autoradiographic assays on brain cryostat sections. The [35S]TBPS binding assay was designed to reveal impaired GABA and channel site coupling shown to be more prominent in recombinant α1/6β3 than in α1/2β3γ2 or β2 subunit-containing GABAA receptors expressed in HEK 293 cells. Increased GABA-insensitive [35S]TBPS binding in the γ2 +/- mouse brains was evident in the cerebral cortex and in subcortical regions, the alterations being regionally similar to the loss of γ2 subnunit-dependent benzodiazepine (BZ) sites as revealed by [ 3H]Ro 15-4513 autoradiography. As the γ2 subunit protein is needed for synaptic clustering of GABAA receptors, these results indicate that the extrasynaptic αβ3 receptors can be visualized in vitro as atypical GABA-insensitive [35S]TBPS binding sites. The results suggest that GABAAergic synaptic inhibition is widely decreased in the brains of anxiety-prone γ2+/- mice, while extrasynaptic GABAA receptors are increased. These autoradiographic imaging findings further demonstrate the need to develop GABAA receptor subtype-selective in vivo ligands to aid in assessing the contributions of various subcellular receptor populations in anxious and other patient groups.",
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Autoradiographic imaging of altered synaptic αβγ2 and extrasynaptic αβ GABAA receptors in a genetic mouse model of anxiety. / Sinkkonen, Saku T.; Luscher, Bernhard; Lüddens, Hartmut; Korpi, Esa R.

In: Neurochemistry International, Vol. 44, No. 7, 01.01.2004, p. 539-547.

Research output: Contribution to journalArticle

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